Audio jack detection circuit

摘要

This document discusses, among other things, a detection system configured to identify a type of a pole of a four-pole audio jack using first and second comparators. The detection system can include a bias circuit configured to bias a detection input coupled to the pole, and first and second comparators configured to compare the detection input to respective first and second thresholds to provide an indication of the type of the pole.

主权项

1. A detection system, comprising:
a bias circuit configured to bias a detection input selectively coupled to a pole of a four-pole audio jack; and first and second comparators configured to compare a value of the detection input to respective first and second thresholds and to provide an indication of a type of the pole, wherein the bias circuit includes:
a bias resistor configured to receive a supply voltage;a current source; anda bias switch configure to selectively couple the current source to the detection input, wherein the current source and the bias switch are in parallel with the bias resistor.